FR2777984A1 - Solar panel which may be used directly as roof construction member and works with heat collection system - Google Patents

Abstract

The panel has a front plate (1) exposed to solar radiation and a rear plate (2). Both plates are made from glass fiber reinforced polyester and form a sandwich with an insulating layer (3) a pipe network to conduct heat away (4) and a fine flexible aluminum grille (7). The pipe network is located between the grille and front plate to maximize heat transfer using an automatically controlled pump and reservoir

Description

- 1 - "Solar panel and solar energy collection device"

DESCRIPTION

  The present invention relates to a solar panel.

  The present invention also relates to a device for collecting solar energy in thermal form. We know solar panels incorporating photovoltaic cells. They are expensive, require elaborate manufacturing facilities and have a

modest energy efficiency.

  There are also known panels designed to produce a greenhouse effect by transforming the solar radiation received on an external face of the panel into thermal radiation emitted by the opposite face. Greenhouse panels do not actually collect energy, but

  rather a transformation of it.

  The purpose of the present invention is to provide a solar energy collection panel which is particularly economical to manufacture and effective on

the energy plan.

  The present invention also relates to a device for collecting solar energy which is

economical and efficient.

  According to a first aspect of the invention, the solar panel is characterized in that it comprises: - a front plate situated on the side exposed to the sun; - a thermally insulating layer adjacent to a rear side of the front plate, opposite to exposure to the sun; - a tube bundle for the circulation of a heat transfer fluid, this bundle being interposed

  between the front plate and the insulating layer.

  -2- The tube bundle collects solar energy in the form of a rise in the temperature of the

coolant.

  Preferably, the solar panel further comprises a thermally conductive sheet interposed between the plate and the thermally insulating layer, and this sheet is in thermal connection with the front plate.

and with the tube bundle.

  The sheet collects the heat developing in the plate under the effect of exposure to the sun, and conducts the heat towards the tube bundle in which said heat is collected by the heat transfer fluid. This reduces the length and complexity of the tube bundle while improving the capture of

  the heat that develops in the front plate.

  It has been found that a particularly suitable thermally conductive sheet is formed

  by a wire mesh, preferably aluminum.

  The panel is preferably of the sandwich type, the insulating layer being disposed between said plate

front and back plate.

  According to a second aspect of the invention, the device for collecting solar energy in thermal form, is characterized in that it comprises: - a reservoir of heat-transfer fluid; - a pump having an intake immersed in the heat transfer fluid of the tank; and - a panel incorporating a tubular bundle for the heat transfer fluid, the panel being disposed at an angle to the horizontal so that the tubular bundle has an upper end, connected to the pump outlet, and a lower end, opening out freely above the

  fluid level in the reservoir.

  -3- Such a device is easily emptied when it is stopped, by reversing the flow. The reverse flow then takes place from the lower end to the upper end and from there into the tank through the pump. Such a draining can be carried out by reversing the direction of operation of the pump. The emptying is even automatic and spontaneous as soon as the pump stops, provided that the pump is of a type where the inlet and outlet communicate with each other at least when the pump is stopped. This is typically a centrifugal type pump or

  another pump of the rotor-turbine type.

  Thus the device according to the invention is particularly suitable for use with the solar panel arranged on the roof. In addition, the heat transfer fluid can consist of water without it

  this results in a risk of degradation by freezing.

  Preferably: the solar energy collection device comprises thermostatic means for cutting off the operation of the pump when a raised operating temperature, such as for example the temperature of the heat transfer fluid in the tank, exceeds a high threshold, and / or to cut the operation of the pump when the temperature of the front plate is lower

at a low threshold.

  - Means are provided for varying the low threshold as a function of a recorded operating temperature, such as for example the temperature of the heat transfer fluid outside the tubular network

  and in particular in the tank.

- the reservoir is a swimming pool.

  According to a third aspect of the invention, the method for producing a panel according to the first aspect comprises: forming in one face of a block of flat foam at least one groove in which a tubular network is placed, then one fixes on said face one

front plate.

  Preferably, a thermally conductive sheet is interposed, in particular an aluminum mesh, on said face of the block before installing the

tubular network.

  Other features and advantages of the invention

  will emerge further from the description below,

  relating to a nonlimiting example.

  In the accompanying drawings: - Figure 1 is a sectional and perspective view of a panel according to the invention; - Figure 2 is a view of a device for

collection according to the invention.

  In the example shown in FIG. 1, the solar panel is produced in the form of a sandwich panel comprising a front plate 1 intended to be exposed to the radiation of the sun and a rear plate 2, both made of polyester reinforced with fibers. of glass. Between the front plate 1 and the rear plate 2 is interposed a thermally insulating layer 3,

  made for example of polyurethane foam.

  According to the invention, a tubular network 4 has been interposed between the front plate 1 and the layer

insulating 3.

  More particularly, the tubular network 4 is housed in corresponding channel-shaped recesses 6 formed in the layer 3 on its face which is

adjacent to the faceplate 1.

  According to a very advantageous feature, a thermally conductive sheet 7 has also been placed between the front plate 1 and the insulating layer 3,

  produced in the form of a fine aluminum mesh.

  Such a mesh is very flexible before its insertion

in the panel.

  -5 - The ply 7 is in thermal connection with the plate

  front 1 and with the tube bundle 4.

  The ply is in contact with the rear face of the front plate in areas located between the tube bundle 4, and forms housings 8 which follow the contour of the recesses 6 to locally bypass each tube of the bundle 4 passing between

  the beam 4 and the insulating layer 3.

  In other words, the bundle 4 is disposed between the ply 7 and the front plate 1. The bundle is heated on the front side by the plate and on all of its

other sides by the tablecloth 7.

  To make the panel shown in Figure 1, we can start by gluing the tubular bundle 4 against the front plate 1, then prefix the ply 7 against the same face of the front plate 1 by making it form bumps everywhere o

  elements of the tube bundle 4 are present.

  Then, the plates 1 and 2 are placed in their desired relative position and the polyurethane foam intended to constitute the insulating layer 3 is formed therebetween, so that this layer comes to trap the sheet 7 and the tubular bundle 4 against the front plate 1, and fix one

to the other the two plates 1 and 2.

  According to another embodiment, which is preferred, a block of foam intended to constitute the layer 3 is produced, a factory in one face of the block at least one groove or groove intended to constitute the housing (s) 6 for the network 4, the sheet 7 is fixed against this face of the block 3, the network 4 is placed, then the front plate 1 is glued. The rear plate 2 can be fixed at any time after the

manufacturing of the foam block.

  The front plate 1 is preferably coated on its front face 9 with a paint or other coating -6- absorbing solar radiation and transforming it into heat with a tendency as reduced as possible to

produce re-emitted radiation.

  The front plate 1 is preferably made of a material as thermally insulating as possible to prevent the heat from being evacuated by possible supporting structures of the panel, such as metal frames or the like. The polyester reinforced with glass fibers is suitable for constituting the front plate 1 by giving it both the qualities of thermal insulation which have just been exposed and the resistance

mechanical desirable.

  An example of sizing is as follows: - thickness of plates 1 and 2: approximately 1 to 2 mm; - thickness of insulating layer 3: approximately 60mm; tube bundle of natural and / or synthetic rubber, outside diameter: 6mm, inside diameter: 4mm; - spacing between the parallel elements of the

tube bundle: about 50mm.

  In the example shown in FIG. 2, three modular panels 11 such as that illustrated in FIG. 1 are mounted side by side to form a roofing panel 12. The panels 11 form an angle 13 relative to the horizontal, by example 30 to 45. Each bundle 4 thus has an upper end 14 and a lower end 16. The ends

  lower 16 are connected to an output 17 au-

  above the level 18 of a coolant reservoir 19. A pump 21 is immersed in the

  tank 19, as well as its inlet orifice 22.

  The discharge 23 of the pump is connected to the

  upper ends 14 of the tubular bundles 4.

  When the device is in operation, the pump 21 takes heat transfer fluid from the reservoir 19 and circulates it in the direction indicated -7- by the arrows P towards the upper ends 14 then through the bundles 4 to the lower ends 16 and from there via the outlet 17 into the tank 19. Not shown, the tank 19 can serve as a hot source for example for a

central heating installation.

  The reservoir 19 can be very large and be constituted in particular by a swimming pool, the water of which, which is to be heated, serves as heat transfer fluid for the

sense of invention.

  The roof 12 can then be a shelter roof next to the swimming pool, or even, in a particularly preferred manner, a roof according to WO-A-97 114, movable between a position of hermetic cover of the swimming pool and a position of next door

of it.

  In a sheltered position, the roof refreshed by thermal sampling is more effective in protecting

  people below.

  The pump 21 is typically of the centrifugal or other rotorturbine type and more generally of a type in which the inlet 22 and the outlet 23 are in communication with each other, at least when the pump is at stop. Thus, as soon as the pump 21 is stopped, the whole system is emptied by siphon effect in the direction (arrows V) opposite to the pumping direction, that is to say from the outlet 17 to the lower ends 16 then to through the beams 4 to the upper ends 14 and from there through the outlet 23, the pump 21 and the inlet port 22. Thus the risk of freezing when the device is stopped is avoided and the heat transfer fluid can simply consist of water. Thermostatic means are provided for regulating

  the temperature of the tank water 19.

  -8- A thermostatic probe 24 is placed in thermal contact with the heat transfer fluid in the reservoir 19. A control device 26 receives the signal from the probe 24, and compares it with a high threshold SH predetermined in a comparator 27, and cuts the operation of the pump 21 when the temperature recorded by the probe 24 is higher than the threshold SH, by means of a switch 28. This thus avoids excessively heating the fluid, in particular if it is a swimming pool whose l water should not generally exceed

  a moderate temperature of 30 to 35 C.

  A thermostatic probe 29 is placed in thermal contact with the front plate 1, and preferably

  with the thermally conductive sheet 7.

  The control unit 26 receives the signal from the probe 29, compares it with a low threshold SB in a comparator 31, and cuts the operation of the pump 21 by means of the switch 28 when the temperature recorded by the probe is lower. at the predetermined low threshold, higher than the freezing temperature

heat transfer fluid.

  This avoids cooling the heat transfer fluid instead of heating it, and prevents freezing of the

coolant.

  In the variant shown, the low threshold SB, instead of being fixed, is equal to the temperature of the heat transfer fluid measured by the probe 24, the signal of which is

  sent to the negative terminal of comparator 31.

  Thus, the device only works when it is actually capable of heating the water of the

tank 19.

  Of course, the invention is not limited to

examples described and shown.

  The realization in the form of autonomous panels as illustrated in FIG. 1 is not essential: one could for example fix the rear face of the thermally insulating layer 3 against a supporting structure such as a wall, a roof slab. The tubular bundle 4 does not necessarily consist of a single tube arranged in a serpentine as shown in FIG. 2. It could for example comprise several tubes in parallel. For better heat transfers but with a higher cost, the beam could be made of metal such

than copper.

  In the embodiment of Figure 2, the use of modular panels is advantageous to allow prefabrication and easy transport on site

  installation, but it is not essential.

  It is not essential that the heat transfer fluid collection tank below the outlet 17 is the same as that in which the inlet orifice 22 of the pump is immersed. There may be two separate tanks, between which extends, for example, a network for using the hot fluid. The spontaneous emptying effect when the pump is stopped is obtained by the simple fact that the outlet orifice 17 is located at a level higher than the level of the reserve in which

bathes the inlet 22.

  Depending on the applications, it is possible to use the device without regulation, or to use only regulation with respect to a low threshold or that the

  regulation with respect to a high threshold.

  The probe 24 could, depending on the applications, be placed elsewhere, for example at the outlet 17 of the network or in contact with a separate use structure.

tank 19.

- 10 -

Claims (16)

  1. Solar panel, characterized in that it comprises: - a front plate (1) located on the side exposed to the sun; - a thermally insulating layer (3) adjacent to a rear side of the front plate, opposite to exposure to the sun; and - a tubular bundle (4) for the circulation of a heat transfer fluid, this bundle being interposed between the front plate (9) and the insulating layer (3).   2. Panel according to claim 1, characterized in that it further comprises a thermally conductive sheet (7) interposed between the front plate (1) and the thermally insulating layer (3) and which is in thermal connection with the front plate (1) and with the tube bundle (4).   3. Panel according to claim 2, characterized in that the ply (7) is in contact with the rear face of the front plate (1) in areas located between the bundle (4), and forms housings (8) for locally bypass each element of the beam (4) passing between the beam (4) and the insulating layer (3).   4. Panel according to claim 2 or 3, characterized in that the ply (7) is a mesh   metallic, preferably aluminum.   5. Panel according to one of claims 1 to 4,   characterized in that the front plate (1) is in synthetic material.   6. Panel according to one of claims 1 to 5,   characterized in that the insulating layer (3) is a synthetic foam.   7. Panel according to one of claims 1 to 6,   characterized in that the panel (11) is of the sandwich type, the insulating layer (3) being arranged between   said front plate (1) and a rear plate (2).   8. Device for collecting solar energy in thermal form, comprising a solar panel according to   one of claims 1 to 7, characterized in that   the collecting device further comprises a reservoir of heat transfer fluid (19) and a pump (21) having an inlet (22) immersed in the heat transfer fluid of the reservoir (19) and in that the panel (11) is arranged in a angle (13) relative to the horizontal so that its tubular bundle (4) has an upper end (14) connected to the discharge (23) of the pump (21) and a lower end (16) opening freely above of   fluid level (18) in the reservoir (19).   9. Device for collecting solar energy according to claim 8, characterized in that the panel   (11) is a roofing panel (12).   10. Device for collecting solar energy according to claim 8 or 9, characterized in that the heat transfer fluid is water.   11. Device for collecting solar energy according to   one of claims 8 to 10, characterized in that   that it includes thermostatic means (24, 27/28) for cutting off the operation of the pump when a recorded operating temperature exceeds a high threshold (SH). 12. Device for collecting solar energy according to   one of claims 8 to 11, characterized in   that it includes thermostatic means (28, 29, 31) for cutting off the operation of the pump when the temperature of a front part (1) of the panel is below a low threshold (SB).   13. Device for collecting solar energy according to claim 12, characterized in that it comprises means for varying the low threshold (SB) in   as a function of a recorded operating temperature.   14. Device for collecting solar energy according to   one of claims 8 to 13, characterized in that the reservoir (19) is a swimming pool.   15. Method for producing a panel according to one   claims 1 to 7, characterized in that   in one face of a flat foam block at least one groove (6) in which a tubular network (4) is placed, then a front plate (1) is fixed on said face. 16. Method according to claim 15, characterized in that one interposes a thermally conductive sheet (7), in particular an aluminum mesh, on said face of the block before putting in places the tubular network (4).